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2 Sheets-Sheet l INVENTURS Yv R bu.

P. C. OSTERMAN ET AL SHUFFLE MUFFLE HEAT TREATING FURNACE o o 0 NI 0 MI.Q .9. & R Q

March 9, 1954 Filed Jan. 10, 1951 Patented Mar. 9, 1954 SHUFFLE MUFFLEHEAT TREATING FURNACE Philip C. Osterman, Elizabeth, and Frederick W.Hombruch, Roselle Park, N. J., assignors to American Gas FurnaceCompany, Elizabeth, N. 1., a corporation of New Jersey ApplicationJanuary 10, 1951, Serial No. 205,272

' 3 Claims. I l

The present invention relates to furnaces for heat treating metals andmore particularly to furnaces wherein the work may be caused to movethrough the heating zone while maintained enveloped in a controlledatmosphere.

A primary aim of the invention is the construction of a furnace withmeans and mechanism arranged automatically to feed the workprogressively from the entrance end thereof through the heating regionsto the delivery end 'while simul- Q which the supporting arms extend aremaintaneously maintaining the work somewhat in a state of agitation andall the while surrounded with a protective gaseous medium suited to thenature of the process or so that oxidation or dis coloration of the workwill not take place.

A further aim of the invention is the construction of a combined muflieand work support adapted to be so actuated from the exterior of thefurnace as to effect progressive movement of the work therealong.

Stillanother objective of the invention is to support a movable mufllein a substantially frictionless manner at a plurality of regions alongthe path traveled by the work to the end of relieving the load on themuilie actuating meansand of prolonging the life of the severalcomponent parts.

Th invention further aims to construct a furnace with a movable muliiesupported in such manner that the heating chamber of the furnace ismaintained closed to the ingresslon of external gases, e. g. atmosphere,that ordinarily would react unfavorably on the work or would tend tolowerthe temperature, and likewise closed to escape therefrom of furnacegases whereby to attain increased furnace efllciency.

Another main objective of the invention is to render available animproved work feeding means that is relatively quiet in operation, whichmay be disposed at a reasonable distance from the heated portion of thefurnace so as to remain uneilected by the heat thereof. that may beconstructed of relatively few parts easily to fabricate and assemble,and which may employ for as its primary power, compressed air, atpressures commonly available in industrial plants.

In carrying forward the aims of this invention it is proposed toconstruct a furnace with a reciprocable muille similar in some respectsto the muflle shown in the patent to A. W. Machlet #2,021,072, butunlike the patent in that, among improved features, the mulile of thepresent invention is supported at its underside by a plurality ofupstanding pivoted arms, the journals of which are disposed below theamine and prefertained fully closed. Th journals themselves are by themanner of mounting, constantly cooled by the ambient air and are readilyaccessible for water cooling if necessary.

The entrance end of the mufile is arranged to extend forwardly out ofthe heating chamber and provided with a flame curtain across itsentrance end through which the work to be treated passes on its way tothe heated regions within the furnace. The delivery end of the muflie isequipped with a down spout through which the work may fall by gravityinto a quench tank. In the preferred embodiment of the invention, themufile and its flame curtain, loading tray and down spout are arrangedto be reciprocated from its forward end by pneumatic piston and cylindermeans whose directions of stroke and the frequencies thereof arecontrolled by a cam actuated reversing. valve, the latter being poweredby a small electric motor geared to provide the reciprocatory speeddesired.

Other objects and advantages will be in part indicated in the followingdescription and in partapprehend the underlying features hereof thatthey may embody the s e in the various ways contemplated by this in'ention, drawings depicting a preferred typicahconstruction have beenannexed as a part of this disclosure and, in such drawings, likecharacters), of reference denote corresponding parts throughout all theviews, of which: 4%

Figure 1 of the drawings illustrates, partly in section, a heattreatingfffurnace embodying the invention.

Fig. 2 is a plan view, partly in section, of

Fig. 3 is a front end elevation of the furnace. Fig. 4 is a rear view ofthe furnace, shown partly in section in two planes. I Fig. 5 is anenlarged plan view of an air motor, valve and valve actuating means,with portions broken away to clarify the principles envolved.

Figs. 6 and 7 are vertical sectional views of one of the pairs of mufllesupports and its mounting. Referring more particularly to Figs. 1-4, thefurnace illustrated comprises a main frame ID, that supports anelongated generally rectangular and hollow furnace ii, the walls ofwhich are 3 constructed of the usual iirebrick and insulating materialsas will be understood. A series of burners II are positioned at suitableintervals in the side walls and by means of which the hollow interior ofthe furnace may be heated to the temperature desired to process thework.

A work supporting and conveying muflie II is disposed within andsubstantially the full length of the combustion chamber ll of thefurnace. The forward end of the tube like muilie extends through thefront end wall of the furnace and is partially cut away to form a workreceiving tray lie. The delivery end of the tunnel is closed butprovided with a discharge tube ll leading into a quench tank "a.customarily the lower end ll of the discharge tube is submerged in thequench liquid, and to prevent upward splash of the quench mediumincident to the falling of the workpieces thereinto the tube is providedwith fluid cascade mechanism indicated at H. Line It indicates a gasline by which a gaseous medium may be introduced into the muflle forprotecting the work, treating, or flushing purposes. Excess gasesescaping from the entrance end of the tunnel are burned at the flamecurtain It provided. A fume exhausting line Ila connects with theinterior of the chute II and leads to a burner lib. Combustion air, andfuel if desired, is supplied to the burner lib by a line lic. By thisconstruction fumes rising from the quench medium are drawn of! andburned and hence do not enter the muine l3.

As illustrated in Figs. 3, 4, and 6, the muiile l! is hollow andgenerally rectangular in crosssection. Its underside rests upon spacedsupports 2|, II, and 2!. Supports II and Il are in pairs and have theirupper ends curved as at 24, with the center of the radius at the axis ofthe shafts newness 1 3|. The pair of supports ll, at the entrance end ofthe muiiie, are also notched at their upper ends to interlock with a ribformed upon the underside of the muiile ll. The lower ends of thesupports 2| are secured to a rock shaft 26 iournaled in bearing brackets21 mounted securely to the main frame ll. The outer end of the rockshaft It carries a lever 20 that has a pivotal connection with a longlink 2!. Link 28 extends under the furnace and is pivotally connectedwith each of rock shafts 30 through the medium of similar levers ll.

Each of the rock shafts ll, in the instant disclosure, there being flvein all, are journaled in bearing brackets 32. The bearing brackets areeach constructed to cradle a pair of supports Ill, and each has closedside and end walls 33 and 34 respectively, with their upper marginsflanged as at ll. The flange OI extends completely around the journalbracket and is securely fastened to the underside of the furnacestructure ll. Within the margins of the flange suitable openings a areprovided in the lower wall of the furnace through which the levers 20project, the lower end of each lever being keyed or otherwise secured toan associated rock shaft 3.. Numeral 31 indicates bearing elements inthe brackets in which each rock shaft may oscillate with case. If, dueto the maintenance of relatively high furnace temperatures, the rockshafts heat up unduly, they may be cooled by passing a cooling agent, e.g. water, through their interiors which are drilled out as at '38 forthat purpose.

In accordance with this invention the entrance end of the mulileprojects through an opening 40 in the furnace and overlays the top ll ofsupplementary frame structure 42. The frame 42 22whichinthisinstanceisintheformofa pair of anti-friction rollers.

The extreme forward end of the mullle is pivotally connected to a shortlink member 48 whichinturnisconnectedtoonearmllofa.

naledinabearingblocklisecurelyfastued cross brace ll. The other arm llof the 4| is relatively long and massive and is connected with a shortlink ll that in otally connects with the upper end of a rod I2. Thepiston rod projects from the upper end of an air motor 53 that ismounted on the shelf 44.

The motor It includes a cylinder member 84, and a cooperating piston IIthat is fastened to the piston rod 52. Above and below the piston, airchambers It and I! respectively are formed in the cylinder, each chamberbeing in communication with an air line II or 5! leading to a controlvalve ill. Inside the cylinder at the undersideof the piston a cushion Iis installed to absorb the shock and noise as the piston reaches thatend of its stroke.

The control valve BI, is of the reversing type having a valve pistonmember 02 reciprocably mounted therein. The piston is formed with twoenlarged valve portions I and M spaced from one another so as to dividethe valve cylinder into three chambers. The center chamber may beregarded as a pressure chamber which constantly communicates with acompressed air line 65, and alternately with cylinder lines 58 and is.The end chambers constantly communicate with exhaust lines 86 and i1,and each in alternation with the cylinder lines it and it as the valvepiston is shifted from one of its extreme positions in the cylinder I toits other extreme position. The core portion "a of the valve piston isarranged to extend through one end of the valve body and normally isurged by a compression spring I, against the face of a hammer cam ll.The cam is in the form of a spiral having an ascending portion "a, anabrupt descending portion llb, and is mounted upon the output shaft of apower transmission herein illustrated as geared motor ll, though otherforms of drive, such as a variable speed drive, may be employed.

When the motor switch (not shown) is closed, the hammer cam II is causedto revolve whereby the piston 82 is moved relatively slowly'to the ill:

' left (Figs. 3 and 5) and then quickly to the right,

in alternation and continuously. When the valve piston is in theposition shown in Fig. 5, compressed air from line I is directed throughthe valve to line I! and reacts against the underside of the motorpiston and the latter moves upwardly. Through the linkage andconnections II, II, ll, 48, 41, and ll, the muiile is withdrawn from thefurnace a limited distance. When the air valve is shifted to the rightin Fig. 5, pressure air is directed to the upper side of the motorpiston and the latter moves downwardly. Through the linkages mentioned,the muflle is thereby caused to move into the furnace a limiteddistance. When the reversing valve is in either of its effectivepositions, air exhausted from the forward side of the motor piston isexpelled through one of the end chambers of the valve and the associatedexhaust line I or 81, as will be understood.

In the positlon of the'parts illustrated in Figs.

, bearing ends 24 are thus caused to move in 1 and 3, the muille It hasbeen withdrawn and is at rest against the stop 15, the piston 55 oftheair motor is in its upper limited position and the valve is still movingto the left and continues so to move until the line 59 leading to thebottom of the air cylinder is wide open. As soon as the hammer cam"revolves sufficiently to let the valve piston move past or down thesteep decline b, the spring 68 shifts the valve quickly to the right.This movementopens the lower end of the cylinder to exhaust and theupper end quickly to pressure from the line 55. Through the linkforwardinto the furnace rather quickly, and the workpieces thereon are alsocarried forward, the

' movement in'the forward direction being assisted by the weight of thearm 50, piston rod 52 and the piston 55. As the mufile moves forward,the

not positively restrained, they are caused to slide a short distancefurther along the muflle when the latter is abruptly stopped by reasonof the ages referred to, the muiile l3 iscaused to move workpiecesgather momentum and as they are son and partake of a rolling motion withthe muille without actually shifting, hence there is no wear on the armsor muflle and the latter can be reciprocated with a minimum effort. Itwill be further observed that with this character of support, the mufflemay be anchored at one end,

preferably the loading end, as by the lever 41 be mounted upon thequench tank lie or be a part of a bracket secured to the main frame it.

Without further analysis, the foregoing will so fully reveal the gist ofthis invention that others can, by applying current knowledge, readily Iadapt it for various utilizations by retaining one muffle. Theworkpieces thereon, which previously had slid forward hold their newpositions and move back with the muiile. As the muflle is brought to astop against the abutment 15, the workpieces, which have not gatheredsumcient momentum to slide, retain their positions on and relative tothe muiiie floor. The pafts are so related and coordinated that oncompletion of the retracting stroke of the muflie, as determined by thestop 15, the valve has still some distance to travel before line 59 isfully opened. In consequence of this relation the piston of the airmotor, and also the muilie, never attain the speed on the retractingstroke that they attain on the forward stroke, with the result that theworkpieces 'slide forward at the end of the forward stroke and holdtheir positions on the muiiie at the end of the retracting stroke. Therepeated cyclic movement of the muffle thus causes the work to advancestep-by-step through the muiile. With the mufiie heated to a giventemperature the rate of progress of the work through the muiiie may becontrolled by varying the stroke imparted to the muiile and the rapiditythereof with due regard to the mass of the individual pieces beingprocessed. On a run of workpieces round by 2 inches long, ten valvecycles per minute gave a desirable feeding rate through the muflie.

As indicated in Fig. l, outward movement of the muiile is limitediby theadjustable screw stop 15, and the inward movement of the muflle islimited by the motor piston 55 engaging the shock absorber 6 I theformer providing a simple means for varying the stroke of reciprocationof the muflle, and the latter a silencer at the end of the forwardstroke.

As the. muiile is reciprocated, the rib 25 on the underside thereofbeing interlocked with rocker arms 2|, causes the arms 2| to oscillatein synchronism. The arms 2| are, as hereinabove explained, operativelyconnected with each of the pairs of rocker arms 20, whereby the latterare also power operated. The upper curved load m.

or more of the features that, from the standpoint of the prior art,fairly constitute essential characteristics of either the generic orspecific aspects of this invention and, therefore, such adaptationsshould be, and are intended to be, comprehended within the meaning andrange of equivalency of the following claims:

Having thus revealed this invention, we claim as new and desire tosecure the following combinations and elements, or equivalents thereof,

by Letters Patent of the United States:

1. A work treating machine combining a furnace having an elongatedheating chamber therein defined by integrallyconnected upper, lower,side and end walls with a work receiving opening in one of the endwalls, an elongated work treating muffle mounted for reciprocation in alinear path within the heating chamber, said muflle having awork-entrance end projecting through the said opening in one of the endwalls, means for supporting the muflle for reciprocation within theheating chamber of the furnace comprising a plurality of longitudinallyspaced muffle-supporting arm members pivotally connected to the exteriorsurface of the lower wall of the furnace and projecting upwardly throughcorrespondingly positioned openings provided in the said lower wall,said arm members having end portions extending into the furnace chamberin abutting relation with the muiile for supporting the latter, each ofsaid arm members havingan end face upon which the muflie rests forsupporting the weight of the muflle shaped in the form of a segment of acylinder having a. radius equal to the radial length of thelatory'movement to the muffle supporting arm members thereby to causetheir respective segmental end faces to move through a circular distanceequal to the linear distance the muilie is reciprocated so thatirrespective of changes in muille length incident to changes intemperature and the resulting changes in the positions of contact withthe end faces of said arm members 7 the reciprocating forces are appliedto the muflle at a pluralit of points lengthwise thereof, said linkagemeans including a two-armed lever movable about a fixed pivot and havingone of its arms connected with the mume and its other arm connected withsaid first named muifle-supporting arms, said two arms being relativelyproportioned to efiect movement of the mumesupporting arms synchronouslywith the linear reciprocations of the muflie.

2. The combination of claim 1 in which said arm members spacedlongitudinally of the iurnace are arranged in pairs and each pair beingsecured on a common rock-shaft and in which the said other arm of thesaid two-armed lever operatively connects with the rock-shaft of eachpair of arms for oscillating the arms of each pair in unison.

3. The combination of claim. 1 in which the pivoted ends of thesupporting arms are journaled in flanged housings, portions 01 whichsurround and form closures for the corresponding armopenings in thelower wall of the furnace to exclude surrounding air from the heatingchamber of the furnace.

PHILIP C. OS'I'ERMAN. FREDERICK W. HORN'BRUCH.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,611,098 Borner Dec. 14, 1926 1,695,950 Carpenter Dec. 18,1928 2,021,072 Machlet Nov. 12, 1935 2,331,419 Patterson Oct. 12, 19432,365,978 Strain Dec. 26, 1944 2,447,393 Campion, Sr. Aug. 17, 19482,473,193 Campion June 14, 1949 2,600,401 Gilbert June 17, 1952 FOREIGNPATENTS Number Country Date 117,849 Australia Dec. 16, 1942

